Difference between revisions of "StellaLight"
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|PINNING=yes | |PINNING=yes | ||
|ECMD={{has_ecmd}} | |ECMD={{has_ecmd}} | ||
| − | |DEPENDS=[[DMX Storage]] (optional) | + | |DEPENDS=[[DMX Storage]] (optional), udpStella (optional) |
|REQUIRES= | |REQUIRES= | ||
| + | |TIMER={{occupies_timer|2}} | ||
|CODE=[https://github.com/ethersex/ethersex/tree/master/services/stella https://github.com/ethersex/ethersex/tree/master/services/stella] | |CODE=[https://github.com/ethersex/ethersex/tree/master/services/stella https://github.com/ethersex/ethersex/tree/master/services/stella] | ||
}} | }} | ||
| Line 86: | Line 87: | ||
')dnl | ')dnl | ||
</source> | </source> | ||
| + | |||
| + | == udp control == | ||
| + | We recommend to use the [[DMX Storage]]. But for easy set ups it is possible to use a simple udp protocol to control stella channels. | ||
| + | Activate protocols->udpStella and configure the port. | ||
| + | A datagram for stella has three bytes: | ||
| + | |||
| + | {| border="1" | ||
| + | ! Byte # | ||
| + | ! Semantic | ||
| + | ! Valid values | ||
| + | |- | ||
| + | | 1 | ||
| + | | Command Byte | ||
| + | | | ||
| + | STELLA_SET_IMMEDIATELY=0, | ||
| + | STELLA_SET_FADE=1, | ||
| + | STELLA_SET_FLASHY=2, | ||
| + | STELLA_SET_IMMEDIATELY_RELATIVE=3, | ||
| + | STELLA_SET_FADESTEP=4, | ||
| + | STELLA_GETALL = 255 | ||
| + | |- | ||
| + | | 2 | ||
| + | | Channel | ||
| + | | 0-15 | ||
| + | |- | ||
| + | | 3 | ||
| + | | Value | ||
| + | | 0-255 | ||
| + | |- | ||
| + | |} | ||
| + | |||
| + | You will get back an UDP datagram if you send the STELLA_GETALL command. It consists of an identifier ["STELLA"]+[Amount of channels]+[channel#1]+..+[channel#n] | ||
== Alternative == | == Alternative == | ||
Latest revision as of 21:21, 2 April 2013
| StellaLight | |
|---|---|
| Status | Stable
|
| menuconfig | Applications->StellaLight: Multichannel pwm |
| Pinning | yes |
| Ecmd | yes |
| Uses Timer | Timer 2 |
| Depends on | DMX Storage (optional), udpStella (optional) |
| Code | https://github.com/ethersex/ethersex/tree/master/services/stella |
StellaLight produces PWM signals on up to 16 independent pins for driving LEDs or servo motors.
Internals
Stella uses an 8-bit Timer of your choice for producing the PWM signals. Since the overflow interrupts need to be very consistent, StellaLight will not work flawlessy when other modules are active that disable the interrupts for a short amount of time.
This is a list of module where you can expect some problems with: Onewire, RFM12 (please add more if you find some).
Moreover StellaLight does not support Gamma Correction since that would require at least 10-12 bit PWM.
Configuration
In Menuconfig you can select the prescaler. The higher the frequency, the more often the StellaLight PWM functions will be executed, leading to an higher overall load of the device. So if you run into problems, try decreasing the frequency, ergo increase the prescaler.
| Option | Prescaler |
|---|---|
| Very slow | 1024 |
| Slow | 256 |
| Normal | 128 |
| Fast | 64 |
You can calculate the resulting frequency by using this formula:
F_CPU: The clockspeed of your AVR (like 8Mhz, 16Mhz etc.)
F_STELLA=F_CPU/Prescaler/512
So given a setting of "Normal" on a 16Mhz device will result in 244Hz which is pretty good for most setups. So more than enough for the human eye (10 times more)
If you have enabled DMX Storage in Menuconfig, you also can set the universe and start channel of StellaLight, so you can control StellaLight via Artnet or DMX FXSlot.
Pinning
| STELLA_PORT1_RANGE(PXI,PXJ) | sets the range (I to J) of StellaLight controlled pins on PORTX |
| STELLA_PORT2_RANGE(PX2I,PX2J) | sets the range (I to J) of StellaLight controlled pins on PORTX2 |
| STELLA_USE_TIMER(I) | programs TimerI for StellaLight |
Two examples:
1. 3 LEDs (e.g. RGB) on PORTA, Pins: 0,1,2
ifdef(`conf_STELLA', `dnl
STELLA_PORT1_RANGE(PA0,PA2)
STELLA_USE_TIMER(2)
')dnl2. 15 LEDs (e.g. 5x RGB) on PORTA, Pins: 0,1,2,3,4,5,6,7 on PORTD, Pins: 0,1,2,3,4,5,6
ifdef(`conf_STELLA', `dnl
STELLA_PORT1_RANGE(PA0,PA7)
STELLA_PORT2_RANGE(PD0,PD6)
STELLA_USE_TIMER(2)
')dnludp control
We recommend to use the DMX Storage. But for easy set ups it is possible to use a simple udp protocol to control stella channels. Activate protocols->udpStella and configure the port. A datagram for stella has three bytes:
| Byte # | Semantic | Valid values |
|---|---|---|
| 1 | Command Byte |
STELLA_SET_IMMEDIATELY=0, STELLA_SET_FADE=1, STELLA_SET_FLASHY=2, STELLA_SET_IMMEDIATELY_RELATIVE=3, STELLA_SET_FADESTEP=4, STELLA_GETALL = 255 |
| 2 | Channel | 0-15 |
| 3 | Value | 0-255 |
You will get back an UDP datagram if you send the STELLA_GETALL command. It consists of an identifier ["STELLA"]+[Amount of channels]+[channel#1]+..+[channel#n]
Alternative
Have a look at Starburst for an improved and more resource-conserving solution.
